This invention relates to electrical feedthroughs, particularly for use in implantable pulse generators (IPG) such as heart pacemakers. It is desirable that feedthroughs for such applications be of miniaturized size and be multi-pin i.e., more than one electrical lead. It is also necessary that the feedthroughs be hermetic, corrosion resistant and impervious to body fluids.
Present IPG feedthroughs typically include an alumina insulator through which an electrical lead passes. The lead is brazed to the alumina with gold. The insulator is brazed to a titanium or niobium ferrule with gold as well. The presence of braze material between lead wires and at the lead wire and insulator junction site makes it difficult to electrically isolate the leads from each other in multi-pin configurations, particularly in miniature sizes, as the conductive braze material tends to reduce the insulation resistance between the leads.